Just a few thoughts
if answers are Yes, Yes, Yes, No, then
This also happens when the Mendix portal is in Maintenance and should be working once the maintenance is completed.
This does sound like a network problem as Rene suggests.
Can you try outside the office, or using a different internet connection? For example, if you have a mobile phone with data, can you try to tether your computer to it and use that while you try to commit. If it works, it will point to the office network being the problem. If it doesn’t work, at least you can rule that out.